The expression "bouncing baby" has been given miraculous new meaning by an 18-month-old boy who fell from a seventh floor window in Paris and survived without a scratch.

The child, left alone in his family flat with his three-year-old sister on Monday evening, climbed out of a window. He then fell 60 feet onto the awning of a café and bounced straight into the arms of a doctor who had rushed across the street to try to help.

The toddler's parents, who have not been named, were still in police custody last night.

The child's escape was even more miraculous than it first appeared. The café, in the 20th arrondissement in north-eastern Paris, was closed for the All Saints bank holiday. The awning which broke the fall should have been folded but had jammed the day before.

Doctor Philippe Bensignor, who caught the child in his arms on the first bounce, had been having a drink in a café across the road.

"My son happened to look up and he saw that a little boy was on the balcony. He had somehow got through the railing and was playing on the very edge of a vertical drop into the street.

"I just had the time to get across the street and place myself. I said to myself: 'whatever happens, I mustn't miss him'."

Dr Bensignor said the little boy tumbled onto "exactly the right spot in the awning, where there was no metal support underneath".

He bounced towards the street and "I caught him in my arms".

"He didn't have a scratch. He cried for a few moments and then calmed down and fell asleep."

Dr Bensignor insisted that he was no hero. "I was just in the right place at the right time," he said. "Anyone else would have done the same thing."

Only the prompt intervention of neighbours on the seventh floor prevented the little boy's sister from falling after him. Samia Benmoussa said that they could hear the little girl crying. She talked to her through the locked door until her brother managed to force the lock and save her from the balcony.

"I said: 'Where is your brother?' and she said: 'He's fallen'. I panicked until I discovered what had happened. It was a real miracle."

The children's parents arrived from a "stroll" two hours later and burst into tears when told about their son's escape. According to police, the explanation of why the children had been left alone was still murky.

"The parents were absent and it's a bit difficult questioning the children, given their age," a spokesman said.

The parents were later arrested for questioning for suspected child neglect and were still in custody last night.